2.1 Dosing Information

The recommended dosage of NOURIANZ is 20 mg administered orally once daily. The dosage may be increased to a maximum of 40 mg once daily, based on individual need and tolerability. Initial dose titration is not required.

NOURIANZ can be taken with or without food [see Clinical Pharmacology (12.3)].

2.2 Dosage Adjustment with Strong CYP3A4 Inhibitors

The maximum recommended dosage of NOURIANZ with concomitant use of strong CYP3A4 inhibitors is 20 mg once daily [see Drug Interactions (7.1)].

2.3 Dosing with Strong CYP3A4 Inducers

Avoid use of NOURIANZ with strong CYP3A4 inducers [see Drug Interactions (7.1)].

2.4 Dosage Adjustment in Patients with Hepatic Impairment

The maximum recommended dosage of NOURIANZ in patients with moderate hepatic impairment (Child-Pugh Class B) is 20 mg once daily. Closely monitor patients with moderate hepatic impairment for adverse reactions when on NOURIANZ treatment [see Adverse Reactions (6.1)]. Avoid use of NOURIANZ in patients with severe hepatic impairment (Child-Pugh Class C) [see Use in Specific Populations (8.7)].

2.5 Dosage Adjustment for Tobacco Smokers

The recommended dosage of NOURIANZ in patients who use tobacco in amounts of 20 or more cigarettes per day (or the equivalent of another tobacco product) is 40 mg once daily [see Use in Specific Populations (8.8) and Clinical Pharmacology (12.3)].

5.1 Dyskinesia

NOURIANZ in combination with levodopa may cause dyskinesia or exacerbate pre-existing dyskinesia.

In controlled clinical trials (Studies 1, 2, 3, and 4) [see Clinical Studies (14)], the incidence of dyskinesia was 15% for NOURIANZ 20 mg, 17% for NOURIANZ 40 mg, and 8% for placebo, in combination with levodopa. One percent of patients treated with either NOURIANZ 20 mg or 40 mg discontinued treatment because of dyskinesia, compared to 0% for placebo.

5.2 Hallucinations / Psychotic Behavior

Because of the potential risk of exacerbating psychosis, patients with a major psychotic disorder should not be treated with NOURIANZ. Consider dosage reduction or discontinuation if a patient develops hallucinations or psychotic behaviors while taking NOURIANZ.

In controlled clinical trials (Studies 1, 2, 3, and 4) [see Clinical Studies (14)], the incidence of hallucinations was 2% for NOURIANZ 20 mg, 6% for NOURIANZ 40 mg, and 3% for placebo. In patients treated with NOURIANZ 40 mg, 1% discontinued because of hallucinations, compared to 0% for placebo and 0% for patients treated with NOURIANZ 20 mg. The incidence of "abnormal thinking and behavior" (paranoid ideation, delusions, confusion, mania, disorientation, aggressive behavior, agitation, or delirium) reported as an adverse reaction was 1% for NOURIANZ 20 mg, 2% for NOURIANZ 40 mg, and 1% for placebo.

5.3 Impulse Control / Compulsive Behaviors

Patients treated with NOURIANZ and one or more medication(s) for the treatment of Parkinson's disease (including levodopa) may experience intense urges to gamble, increased sexual urges, intense urges to spend money, binge or compulsive eating, and/or other intense urges, and the inability to control these urges. In controlled clinical trials (Studies 1, 2, 3 and 4) [see Clinical Studies (14)], one patient treated with NOURIANZ 40 mg was reported to have impulse control disorder, compared to no patient on placebo or NOURIANZ 20 mg.

In some postmarketing cases, these urges were reported to have stopped when the dose was reduced, or the medication was discontinued. Because patients may not recognize these behaviors as abnormal, it is important for prescribers to specifically ask patients or their caregivers about the development of new or increased gambling urges, sexual urges, uncontrolled spending, binge or compulsive eating, or other urges while being treated with NOURIANZ. Consider dose reduction or discontinuation if a patient develops such urges while taking NOURIANZ [see Adverse Reactions (6.2)].

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety of NOURIANZ was evaluated in 734 patients with Parkinson's disease (PD) taking a stable dose of levodopa and a DOPA decarboxylase inhibitor, with or without other PD medications, in four randomized, multicenter, double-blind, placebo-controlled trials 12 weeks in duration (Studies 1, 2, 3 and 4) [see Clinical Studies (14)]. Of the patient population exposed to NOURIANZ, 50% were male, 32% White, 67% Asian, and the mean age was 65 years (range: 33 to 84 years). Of these patients, 356 received NOURIANZ 20 mg and 378 received NOURIANZ 40 mg.

6.2 Postmarketing Experience

The following adverse reaction has been identified during post approval use of istradefylline outside of the United States. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure: increased libido.

7.1 Effect of Other Drugs on NOURIANZ

7.2 Effect of NOURIANZ on Other Drugs

8.1 Pregnancy

8.2 Lactation

8.3 Females and Males of Reproductive Potential

8.4 Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

8.5 Geriatric Use

No adjustment of NOURIANZ dosage is recommended on the basis of age. Of the total number of PD patients who received NOURIANZ in clinical trials, 53% were ≥65 years and 13% were ≥75 years of age. No overall differences in effectiveness were observed between these patients and younger patients.

8.6 Renal Impairment

No adjustment of NOURIANZ dosage is needed in patients with mild renal impairment (estimated creatinine clearance (CrCL) by Cockcroft-Gault equation: 60-89 mL/min), moderate renal impairment (CrCL 30-59 mL/min), or severe renal impairment (CrCL 15-29 mL/min). NOURIANZ has not been evaluated in patients with end-stage renal disease (ESRD) (CrCL <15 mL/min) or ESRD requiring hemodialysis [see Clinical Pharmacology (12.3)].

8.7 Hepatic Impairment

No adjustment of NOURIANZ dosage is needed in patients with mild hepatic impairment (Child-Pugh Class A).

In patients with moderate hepatic impairment (Child-Pugh Class B), the steady-state exposures (AUC0-24h) were predicted to be 3.3-fold higher than in healthy subjects, based on the estimated mean terminal half-life. Therefore, the maximum recommended dosage of NOURIANZ in patients with moderate hepatic impairment (Child-Pugh Class B) is 20 mg once daily [see Clinical Pharmacology (12.3)]. Closely monitor patients with moderate hepatic impairment for adverse events when on NOURIANZ treatment [see Adverse Reactions (6.1)].

NOURIANZ has not been studied in patients with severe hepatic impairment (Child-Pugh Class C). Avoid use of NOURIANZ in patients with severe hepatic impairment [see Clinical Pharmacology (12.3)].

8.8 Tobacco Smokers

Tobacco smoking decreased NOURIANZ steady-state systemic exposures by 38% to 54% [see Clinical Pharmacology (12.3)], which may decrease efficacy. Therefore, the recommended NOURIANZ dosage in patients who smoke 20 or more cigarettes per day (or the equivalent amount of another tobacco product) is 40 mg once daily.

10.1 Human Experience

There is limited clinical experience regarding human overdosage with NOURIANZ. In clinical trials, one patient took 6 tablets (120 mg, 3 times the maximum recommended dosage) of istradefylline with alcoholic beverages and developed hallucinations, agitation, and worsening dyskinesia.

10.2 Management of Overdose

There are no known specific antidotes for NOURIANZ nor any specific treatment for istradefylline overdose. If an overdose occurs, NOURIANZ treatment should be discontinued and supportive treatment should be administered as clinically indicated. Consider the long terminal half-life of istradefylline (about 83 hours) and the possibility of multiple drug involvement.

Consult a Certified Poison Control Center for up-to-date guidance and advice.

12.1 Mechanism of Action

The precise mechanism by which istradefylline exerts its therapeutic effect in Parkinson’s disease is unknown. In in vitro studies and in in vivo animal studies, istradefylline was demonstrated to be an adenosine A2A receptor antagonist.

12.2 Pharmacodynamics

12.3 Pharmacokinetics

Istradefylline exhibits dose-proportional pharmacokinetics after multiple oral doses from 20 mg to 80 mg (2 times the maximum recommended dosage). Steady-state was reached within 2 weeks of once-daily dosing. The pharmacokinetics of istradefylline were similar in PD patients and healthy subjects.

13.1 Carcinogenesis, Mutagenesis, and Impairment of Fertility

13.2 Animal Toxicology and/or Pharmacology

Oral administration of istradefylline (0, 30, 100, or 320 mg/kg/day) to rats for two years resulted in an increase in the incidence and severity of vascular mineralization in the brain (including in the caudate/putamen, globus pallidus, thalamus, and nucleus accumbens) at all doses tested. The vascular mineralization was composed of calcium and phosphorus and, at higher doses, were reported to partially or completely occlude the blood vessels. There was no evidence of neuronal degeneration, inflammation, or glial response associated with the foci of mineralization.

Brain mineralization was not detected in mice administered istradefylline (0, 25, 125, or 250 mg/kg/day) orally for two years or in dogs administered istradefylline (0, 10, 30, or 100 mg/kg/day) orally for 52 weeks.

16.1 How Supplied

NOURIANZ (istradefylline) tablets are available as:

20 mg Tablets:

Peach-colored, pillow-shaped, film-coated tablets with "20" debossed on one side.

Bottle of 90: NDC 42747-602-90

40 mg Tablets:

Peach-colored, almond-shaped, film-coated tablets with "40" debossed on one side.

Bottle of 90: NDC 42747-604-90

16.2 Storage and Handling

Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F to 86°F) [see USP Controlled Room Temperature].

Dyskinesia

Advise patients that NOURIANZ may cause dyskinesia or exacerbate pre-existing dyskinesia [see Warnings and Precautions (5.1)].

Hallucinations / Psychotic Behavior

Advise patients that NOURIANZ may cause hallucinations or psychotic behavior and they should report any of these adverse reactions to their healthcare provider [see Warnings and Precautions (5.2)].

Impulse Control / Compulsive Behaviors

Inform patients that they may experience intense urges to gamble, increased sexual urges, and other intense urges and the inability to control these urges while taking NOURIANZ and one or more medication(s) for the treatment of Parkinson's disease (including levodopa). Advise patients that they should report any of these adverse reactions to their healthcare provider [see Warnings and Precautions (5.3)].

Concomitant Medications

Certain medications can cause an interaction with NOURIANZ. Advise patients to inform their healthcare provider about their smoking status and about all of the medicines they are taking or plan to take, including over-the-counter medicines, dietary supplements, and herbal products [see Drug Interactions (7.1, 7.2) and Use in Specific Populations (8.8)].